Radio frequency module and communication device

ABSTRACT

A radio frequency module includes: a first filter circuit disposed on a first path that connects an antenna terminal and a first input/output terminal, and having a passband that is a first frequency band; a second filter circuit disposed on a second path that connects the antenna terminal and a second input/output terminal, and having a passband that is a second frequency band higher than the first frequency band; and a band-elimination filter circuit disposed on the second path and having an attenuation band that is a partial band of a third frequency band that belongs to an unlicensed band ranging from 5 GHz or higher, and is higher than the second frequency band. The second filter circuit is an LC filter circuit that includes an inductor and a capacitor.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 17/066,772 filed on Oct. 9, 2020, which claims priority ofJapanese Patent Application No. 2019-188470 filed on Oct. 15, 2019. Theentire disclosure of each of the above-identified applications,including the specification, drawings and claims is incorporated hereinby reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a radio frequency module and acommunication device.

BACKGROUND

In recent communication service, the width of a communication band isincreased, and a plurality of communication bands are simultaneouslyused, in order to increase channel capacity and the speed ofcommunication.

Japanese Unexamined Patent Application Publication No. 2006-128881discloses a multiplexer that can demultiplex and multiplex radiofrequency signals of two different communication bands. The multiplexerdisclosed in Japanese Unexamined Patent Application Publication No.2006-128881 includes an LC filter that includes an inductor and acapacitor. According to this, radio frequency signals of widecommunication bands can be demultiplexed and multiplexed.

BRIEF SUMMARY

The Third Generation Partnership Project (3GPP) has defined simultaneoustransfer of radio frequency signals of 5G-New Radio (NR) frequency bandssuch as n77 (from 3300 MHz to 4200 MHz), n78 (from 3300 MHz to 3800MHz), and n79 (from 4400 MHz to 5000 MHz). Furthermore, when a 5G-NRradio frequency signal of such a band and a radio frequency signal of anunlicensed band that ranges from 5 GHz or higher and is close to theband are simultaneously transferred, it is necessary to maintaincommunication quality such as an isolation between the 5G-NR radiofrequency signal and the radio frequency signal of the unlicensed band.

However, it is difficult to apply the LC filter described in JapaneseUnexamined Patent Application Publication No. 2006-128881 as a diplexerthat demultiplexes and multiplexes a 5G-NR signal of such a band and asignal of the unlicensed band that ranges from 5 GHz or higher and isclose to the band. For example, an LC filter is suitable as a filterthat passes a signal of a wide band such as n79, but is unsuitable forattenuating a signal of an adjacent band whose frequency interval toanother band is relatively narrow. Furthermore, a filter that passes asignal of n79 also needs isolation between signals of n79 and n77 thathas a lower frequency range than n79. Accordingly, the filter thatpasses a signal of n79 needs to attenuate both of a signal having alower frequency range (n77) and a signal having a higher frequency range(the unlicensed band) than the passband. However, it is difficult for anLC filter to fully attenuate both of the signals having lower and higherfrequency ranges than the passband, while ensuring a wide passband. Onthe other hand, (i) a band used for n79 varies among countries and (ii)a band used for the unlicensed band (for example, Wi-Fi® (a registeredtrademark)) may not be close to n79 depending on a channel used, andthus communication quality may not deteriorate even if signals of suchbands are simultaneously transferred. Specifically, a filter that passesa signal of n79 that is a wide frequency band needs to have optimizedcommunication quality such as isolation and transfer loss, according toa state of simultaneously using the unlicensed band and n79 adjacent toeach other.

In view of the above, the present disclosure has been conceived in orderto solve the above-identified and other problems, and provides a radiofrequency module and a communication device that can reducedeterioration of communication quality when a radio frequency signal ofan unlicensed band ranging from 5 GHz or higher and a signal of a wideband adjacent to the unlicensed band are simultaneously used.

In order to provide such a radio frequency module, a radio frequencymodule according to an aspect of the present disclosure includes: anantenna terminal; a first input/output terminal; a second input/outputterminal; a first filter circuit disposed on a first path and having apassband that is a first frequency band, the first path connecting theantenna terminal and the first input/output terminal; a second filtercircuit disposed on a second path and having a passband that is a secondfrequency band higher than the first frequency band, the second pathconnecting the antenna terminal and the second input/output terminal;and a first band-elimination filter circuit disposed on the second pathand having an attenuation band that is a partial band of a thirdfrequency band belonging to an unlicensed band that ranges from 5 GHz orhigher, the third frequency band being higher than the second frequencyband. The second filter circuit is an LC filter circuit that includes aninductor and a capacitor.

According to the present disclosure, a radio frequency module and acommunication device can be provided which can reduce deterioration ofcommunication quality when a radio frequency signal of an unlicensedband ranging from 5 GHz or higher and a signal of a wide band adjacentto the unlicensed band are simultaneously used.

BRIEF DESCRIPTION OF DRAWINGS

These and other advantages and features will become apparent from thefollowing description thereof taken in conjunction with the accompanyingDrawings, by way of non-limiting examples of embodiments disclosedherein.

FIG. 1A illustrates a circuit configuration of a radio frequency moduleand a communication device according to Embodiment 1.

FIG. 1B illustrates a circuit configuration of the radio frequencymodule and a communication device according to Variation 1 of Embodiment1.

FIG. 2A illustrates a first example of communication bands and filterpassing characteristics applied to the radio frequency module accordingto Embodiment 1 and Variation 1.

FIG. 2B illustrates a second example of communication bands and filterpassing characteristics applied to the radio frequency module accordingto Embodiment 1 and Variation 1.

FIG. 2C illustrates a third example of communication bands and filterpassing characteristics applied to the radio frequency module accordingto Embodiment 1 and Variation 1.

FIG. 2D illustrates a fourth example of communication bands and filterpassing characteristics applied to the radio frequency module accordingto Embodiment 1 and Variation 1.

FIGS. 3A to 3C illustrate a first example of configurations of aband-elimination filter circuit according to Embodiment 1.

FIG. 4A illustrates a circuit configuration of a radio frequency moduleaccording to Variation 2 of Embodiment 1.

FIG. 4B illustrates a circuit configuration of a radio frequency moduleaccording to Variation 3 of Embodiment 1.

FIG. 4C illustrates a circuit configuration of a radio frequency moduleaccording to Variation 4 of Embodiment 1.

FIGS. 5A to 5C illustrate a circuit configuration of a radio frequencymodule according to Variation 5 of Embodiment 1.

FIGS. 6A to 6D illustrate circuit configurations of a radio frequencymodule according to Variation 6 of Embodiment 1.

FIG. 7 illustrates a circuit configuration of a radio frequency moduleand a communication device according to Embodiment 2.

FIG. 8 illustrates an example of communication bands and filter passingcharacteristics applied to the radio frequency module according toEmbodiment 2.

FIG. 9A illustrates a circuit configuration of a radio frequency moduleand a communication device according to Embodiment 3.

FIG. 9B illustrates a circuit configuration of the radio frequencymodule and a communication device according to a variation of Embodiment3.

FIG. 10A illustrates a first example of filter passing characteristicsof the radio frequency module according to Embodiment 3 and thevariation thereof.

FIG. 10B illustrates a second example of filter passing characteristicsof the radio frequency module according to Embodiment 3 and thevariation thereof.

DETAILED DESCRIPTION OF EMBODIMENTS

The following describes in detail the embodiments of the presentdisclosure, with reference to drawings. Note that the embodiments andvariations described below each show a general or specific example. Thenumerical values, shapes, materials, elements, the arrangement andconnection of the elements, and others indicated in the followingembodiments and variations are mere examples, and therefore are notintended to limit the present disclosure. Thus, among the elements inthe following embodiments and variations, elements not recited in anyindependent claim are described as arbitrary elements. In addition, thesizes of elements and the ratios of the sizes illustrated in thedrawings are not necessarily accurate.

In the following, a “path” means a transfer route that includes, forinstance, a line through which a radio frequency signal propagates, anelectrode directly connected to the line, or a terminal directlyconnected to the line or the electrode.

Embodiment 1

1.1 Configuration of Radio Frequency Module 1 and Communication Device 7

FIG. 1A illustrates a circuit configuration of radio frequency module 1and communication device 7 according to Embodiment 1. As illustrated inFIG. 1A, communication device 7 includes radio frequency module 1,wireless local-area network (WLAN) circuit 2, radio frequency (RF)signal processing circuits (RF integrated circuits (RFICs)) 3 and 4,baseband signal processing circuit (BB integrated circuit (BBIC)) 5, andantennas 61 and 62.

RFIC 3 is an RF signal processing circuit that processes radio frequencysignals of a first frequency band and a second frequency bandtransmitted and received by antenna 61. Specifically, RFIC 3 processes areception signal input through a reception path of radio frequencymodule 1 by down-conversion, for instance, and outputs a receptionsignal generated by being processed to BBIC 5. RFIC 3 processes atransmission signal input from BBIC 5 by up-conversion, for instance,and outputs a transmission signal generated by being processed to atransmission path of radio frequency module 1.

BBIC 5 is a circuit that processes signals using an intermediatefrequency band lower than the frequency range of a radio frequencysignal transferred in radio frequency module 1. A signal processed byBBIC 5 is used, for example, as an image signal for image display or asan audio signal for talk through a loudspeaker.

RFIC 4 is an RF signal processing circuit that processes radio frequencysignals of a third frequency band transmitted and received by antenna62. Specifically, RFIC 4 processes reception signals input through areception path of WLAN circuit 2. RFIC 4 outputs transmission signals toa transmission path of WLAN circuit 2.

Antenna 61 radiates and receives radio frequency signals of the firstfrequency band and the second frequency band. Antenna 62 radiates andreceives radio frequency signals of the third frequency band.

Note that in the present embodiment, the second frequency bandcorresponds to a communication band close to the lowest frequency of anunlicensed band ranging from 5 GHz or higher and is, for example, acommunication band of 4G-Long Term Evolution)(LTE®) or 5G-New Radio(NR). In particular, the second frequency band is, for example, n79(4400 MHz to 5000 MHz) of 5G-NR having a narrow frequency interval tothe unlicensed band.

In the present embodiment, the first frequency band corresponds to acommunication band close to the lowest frequency of the second frequencyband and is, for example, a 4G-LTE or 5G-NR communication band. Inparticular, the first frequency band is at least one of, for example,5G-NR n77 (3300 MHz to 4200 MHz), 5G-NR n78 (3300 MHz to 3800 MHz),5G-NR n42 (3400 MHz to 3600 MHz), 5G-NR n48 (3550 MHz to 3700 MHz), or4G-LTE® B48 (3550 MHz to 3700 MHz).

In the present embodiment, the third frequency band corresponds to acommunication band belonging to the unlicensed band ranging from 5 GHzor higher. The third frequency band is, for example, WLAN (Wi-Fi®: 5.15GHz to 5.85 GHz), B46 (5.15 GHz to 5.925 GHz) of License-Assisted Access(LAA), or NR-U (5.15 GHz to 7.125 GHz).

Radio frequency module 1 includes antenna terminal 100, input/outputterminals 110 and 120, filter circuits 11 and 12, band-eliminationfilter circuit 13, switches 14, 15, 18, and 19, transmission amplifiers16T and 17T, and reception amplifiers 16R and 17R.

Antenna terminal 100 is connected to antenna 61.

Filter circuit 12 is an example of a first filter circuit, and is afilter disposed on a first path that connects antenna terminal 100 andinput/output terminal 120 (a first input/output terminal), and having apassband that is a first frequency band.

Filter circuit 11 is an example of a second filter circuit, and is afilter disposed on a second path that connects antenna terminal 100 andinput/output terminal 110 (a second input/output terminal), and having apassband that is a second frequency band higher than the first frequencyband. Filter circuit 11 is a so-called LC filter that includes aninductor and a capacitor.

Band-elimination filter circuit 13 is an example of a firstband-elimination filter circuit, and is a tunable band-eliminationfilter disposed on the second path, and having an attenuation band thatis a partial band of a third frequency band that is higher than thesecond frequency band and belongs to the unlicensed band ranging from 5GHz or higher. Specifically, band-elimination filter circuit 13 changesat least one of a frequency range or an amount of attenuation of theattenuation band.

Note that in radio frequency module 1 according to the presentembodiment, filter circuits 11 and 12 are directly connected to antennaterminal 100. Specifically, filter circuits 11 and 12 are included in adiplexer that demultiplexes and multiplexes a radio frequency signal ofthe first frequency band and a radio frequency signal of the secondfrequency band. Accordingly, radio frequency module 1 is furtherminiaturized.

Note that filter circuits 11 and 12 do not need to be directly connectedto antenna terminal 100. In this case, a switch may be disposed betweenantenna terminal 100 and filter circuits 11 and 12, which switchesbetween the connection/disconnection of antenna terminal 100 to/fromfilter circuit 11 and switches between the connection/disconnection ofantenna terminal 100 to/from filter circuit 12.

Transmission amplifier 16T is a power amplifier that amplifies a radiofrequency signal of the second frequency band input via input/outputterminal 110. Transmission amplifier 17T is a power amplifier thatamplifies a radio frequency signal of the first frequency band input viainput/output terminal 120.

Reception amplifier 16R is a low noise amplifier that amplifies a radiofrequency signal of the second frequency band while noise is kept low,and outputs the amplified signal to input/output terminal 110. Receptionamplifier 17R is a low noise amplifier that amplifies a radio frequencysignal of the first frequency band while noise is kept low, and outputsthe amplified signal to input/output terminal 120.

Switch 14 includes a common terminal and two selection terminals. Thecommon terminal of switch 14 is connected to band-elimination filtercircuit 13. Out of the selection terminals, one selection terminal ofswitch 14 is connected to transmission amplifier 16T, and the otherselection terminal of switch 14 is connected to reception amplifier 16R.This connection configuration allows switch 14 to switch the connectionof the common terminal between the one selection terminal and the otherselection terminal. Specifically, switch 14 switches the connection ofband-elimination filter circuit 13 between transmission amplifier 16Tand reception amplifier 16R. Switch 14 includes a single pole doublethrow (SPDT) switch circuit, for example.

Switch 18 includes a common terminal and two selection terminals. Thecommon terminal of switch 18 is connected to input/output terminal 110.Out of the selection terminals, one selection terminal of switch 18 isconnected to transmission amplifier 16T, and the other selectionterminal of switch 18 is connected to reception amplifier 16R. Thisconnection configuration allows switch 18 to switch the connection ofthe common terminal between the one selection terminal and the otherselection terminal. Specifically, switch 18 switches the connection ofinput/output terminal 110 between transmission amplifier 16T andreception amplifier 16R. Switch 18 includes an SPDT switch circuit, forexample.

Switch 15 includes a common terminal and two selection terminals. Thecommon terminal of switch 15 is connected to filter circuit 12. Out ofthe selection terminals, one selection terminal of switch 15 isconnected to transmission amplifier 17T, and the other selectionterminal of switch 15 is connected to reception amplifier 17R. Thisconnection configuration allows switch 15 to switch the connection ofthe common terminal between the one selection terminal and the otherselection terminal. Specifically, switch 15 switches the connection offilter circuit 12 between transmission amplifier 17T and receptionamplifier 17R. Switch 15 includes an SPDT switch circuit, for example.

Switch 19 includes a common terminal and two selection terminals. Thecommon terminal of switch 19 is connected to input/output terminal 120.Out of the selection terminals, one selection terminal of switch 19 isconnected to transmission amplifier 17T, and the other selectionterminal of switch 19 is connected to reception amplifier 17R. Thisconnection configuration allows switch 19 to switch the connection ofthe common terminal between the one selection terminal and the otherselection terminal. Specifically, switch 19 switches the connection ofinput/output terminal 120 between transmission amplifier 17T andreception amplifier 17R. Switch 19 includes an SPDT switch circuit, forexample.

Synchronous switching of switches 14 and 18 allows the second path thatconnects antenna terminal 100 and input/output terminal 110 to convey atransmission signal and a reception signal of the second frequency bandusing the time division duplex (TDD) scheme.

Synchronous switching of switches 15 and 19 allows the first path thatconnects antenna terminal 100 and input/output terminal 120 to convey atransmission signal and a reception signal of the first frequency bandusing the TDD scheme.

Note that radio frequency module 1 may transfer radio frequency signalsof the first frequency band and the second frequency band using thefrequency division duplex (FDD) scheme.

Note that one of switches 14 and 18 may not be included. Furthermore,one of switches 15 and 19 may not be included.

WLAN circuit 2 includes antenna terminal 200, input/output terminal 210,filter circuit 21, switches 22 and 24, transmission amplifier 23T, andreception amplifier 23R.

Antenna terminal 200 is connected to antenna 62.

Filter circuit 21 is an example of a third filter circuit, and is afilter disposed on a path that connects antenna terminal 200 andinput/output terminal 210, and has a passband that is the thirdfrequency band.

Transmission amplifier 23T is a power amplifier that amplifies a radiofrequency signal of the third frequency band input via input/outputterminal 210. Reception amplifier 23R is a low noise amplifier thatamplifies a radio frequency signal of the third frequency band whilenoise is kept low, and outputs the amplified signal to input/outputterminal 210.

Switch 22 includes a common terminal and two selection terminals. Thecommon terminal of switch 22 is connected to filter circuit 21. Out ofthe selection terminals, one selection terminal of switch 22 isconnected to transmission amplifier 23T, and the other selectionterminal of switch 22 is connected to reception amplifier 23R. Thisconnection configuration allows switch 22 to switch the connection ofthe common terminal between the one selection terminal and the otherselection terminal. Thus, switch 22 switches the connection of filtercircuit 21 between transmission amplifier 23T and reception amplifier23R. Switch 22 includes an SPDT switch circuit, for example.

Switch 24 includes a common terminal and two selection terminals. Thecommon terminal of switch 24 is connected to input/output terminal 210.Out of the selection terminals, one selection terminal of switch 24 isconnected to transmission amplifier 23T, and the other selectionterminal of switch 24 is connected to reception amplifier 23R. Thisconnection configuration allows switch 24 to switch the connection ofthe common terminal between the one selection terminal and the otherselection terminal. Specifically, switch 24 switches the connection ofinput/output terminal 210 between transmission amplifier 23T andreception amplifier 23R. Switch 24 includes an SPDT switch circuit, forexample.

Synchronous switching of switches 22 and 24 allows a path that connectsantenna terminal 200 and input/output terminal 210 to convey atransmission signal and a reception signal of the third frequency bandusing the TDD scheme.

Note that WLAN circuit 2 may transfer a radio frequency signal of thethird frequency band using the FDD scheme.

WLAN circuit 2 may be included in radio frequency module 1.

Note that one of switches 22 and 24 may not be included.

According to the configuration of radio frequency module 1 according tothe present embodiment, an LC filter forms filter circuit 11 that passesa signal of the second frequency band close to the third frequency bandbelonging to the unlicensed band ranging from 5 GHz or higher, and thusthe width of the passband of filter circuit 11 can be increased. Filtercircuit 11 may have an attenuation band that is the first frequency bandlower than the second frequency band. On the other hand, filter circuit11 is an LC filter, and thus cannot sufficiently ensure the amount ofattenuation of the third frequency band. To address this,band-elimination filter circuit 13 having an attenuation band that is apartial band of the third frequency band is disposed on the second pathon which filter circuit 11 is disposed. According to whether a radiofrequency signal of the second frequency band is used simultaneouslywith a radio frequency signal of the third frequency band,band-elimination filter circuit 13 changes at least one of the frequencyrange or the amount of attenuation of the third frequency band.Furthermore, according to a certain partial band of the third frequencyband of radio frequency signals used simultaneously with radio frequencysignals of the second frequency band, band-elimination filter circuit 13changes at least one of the frequency range or the amount of attenuationof the certain partial band. Accordingly, a high isolation can beensured according to the state of simultaneously using the secondfrequency band and the third frequency band close to each other. Acircuit configuration that highly attenuates a signal of the thirdfrequency band is not added to filter circuit 11, and low loss of thepassband is ensured, so that when the second frequency band is not usedsimultaneously with the third frequency band, a transfer loss of a radiofrequency signal of the second frequency band can be reduced by notallowing band-elimination filter circuit 13 to operate.

Accordingly, while filter circuit 11 reduces the transfer loss of thesecond frequency band, band-elimination filter circuit 13 can ensure thehigh isolation when a radio frequency signal of the second frequencyband and a radio frequency signal of the unlicensed band ranging from 5GHz or higher are simultaneously used. Thus, it is possible to provideradio frequency module 1 and communication device 7 that can reducedeterioration of communication quality when a radio frequency signal ofthe unlicensed band ranging from 5 GHz or higher and a signal of a wideband close to the unlicensed band are simultaneously used.

Note that filter circuit 11 includes one or more series-arm circuitsdisposed on the second path, for example. Band-elimination filtercircuit 13 includes one or more series-arm circuits disposed on thesecond path, and one or more parallel-arm circuits, for example. Here, acapacitive series-arm circuit of filter circuit 11 and a capacitiveseries-arm circuit of the band-elimination filter circuit may bedirectly connected to each other. Note that even if the capacitiveseries-arm circuit of filter circuit 11 and the capacitive series-armcircuit of the band-elimination filter circuit are connected to eachother via a switch, equivalent advantageous effects are yielded when theswitch is conducting.

Accordingly, the impedance between filter circuit 11 andband-elimination filter circuit 13 can be readily matched, and a radiofrequency signal of the second frequency band can be transferred throughthe second path while loss is kept low.

In radio frequency module 1 according to the present embodiment, thefirst path and the second path may be included in any of a receptioncircuit that only receives signals, a transmission circuit that onlytransmits signals, a transmission and reception circuit that transmitsand also receives signals.

FIG. 1B illustrates a circuit configuration of radio frequency module 1and communication device 7A according to Variation 1 of Embodiment 1. Asillustrated in FIG. 1B, communication device 7A includes radio frequencymodule 1, WLAN circuit 2A, RFICs 3 and 4, BBIC 5, and antennas 61 and62. Communication device 7A according to this variation is differentfrom communication device 7 according to Embodiment 1 in theconfiguration of WLAN circuit 2A. The following describes communicationdevice 7A according to this variation, focusing on differences fromcommunication device 7 according to Embodiment 1.

WLAN circuit 2A includes antenna terminal 200, input/output terminal210, filter circuit 21, band-elimination filter circuit 25, switches 22and 24, transmission amplifier 23T, and reception amplifier 23R.

Antenna terminal 200 is connected to antenna 62.

Filter circuit 21 is an example of a third filter circuit, and is afilter disposed on a third path that connects antenna terminal 200 andinput/output terminal 210, and having a passband that is the thirdfrequency band.

Band-elimination filter circuit 25 is an example of a secondband-elimination filter circuit, and is a band-elimination filterdisposed on a third path and having an attenuation band that is apartial band of the second frequency band. Band-elimination filtercircuit 25 changes at least one of the frequency range or the amount ofattenuation of the attenuation band.

Note that the frequency range and the amount of attenuation of theattenuation band may be fixed (alternatively, may not be changed) inband-elimination filter circuit 25.

Switch 22 includes a common terminal and two selection terminals. Thecommon terminal of switch 22 is connected to band-elimination filtercircuit 25. Out of the selection terminals, one selection terminal ofswitch 22 is connected to transmission amplifier 23T, and the otherselection terminal of switch 22 is connected to reception amplifier 23R.This connection configuration allows switch 22 to switch the connectionof the common terminal between the one selection terminal and the otherselection terminal. Specifically, switch 22 switches the connection ofband-elimination filter circuit 25 between transmission amplifier 23Tand reception amplifier 23R. Switch 22 includes an SPDT switch circuit,for example.

According to the configuration of WLAN circuit 2A according to thisvariation, band-elimination filter circuit 25 having an attenuation bandthat is a partial band of the second frequency band is disposed on thethird path on which filter circuit 21 is disposed. According to whethera radio frequency signal of the third frequency band is usedsimultaneously with a radio frequency signal of the second frequencyband, band-elimination filter circuit 25 changes at least one of thefrequency range or the amount of attenuation of the second frequencyband. Furthermore, according to a certain partial band of the secondfrequency band of a radio frequency signal used simultaneously with aradio frequency signal of the third frequency band, band-eliminationfilter circuit 25 changes at least one of the frequency range or theamount of attenuation of the certain partial band. Accordingly, a highisolation can be ensured according to the state of simultaneously usingthe third frequency band and the second frequency band close to eachother. When the third frequency band is not used simultaneously with thesecond frequency band, transfer loss of a radio frequency signal of thethird frequency band can be reduced by not allowing band-eliminationfilter circuit 25 to operate.

Note that WLAN circuit 2A may be included in radio frequency module 1.

1.2 Communication Band and Filter Passing Characteristics Applied toRadio Frequency Module

FIG. 2A illustrates a first example of communication bands and filterpassing characteristics applied to radio frequency module 1 according toEmbodiment 1 and Variation 1. Note that in the examples in FIGS. 2A to2D, 5G-NR n77, for example, is applied as the first frequency band,5G-NR n79, for example, is applied as the second frequency band, and oneof WLAN (Wi-Fi®) of the unlicensed band, B46 of LAA, and NR-U, forexample, is applied as the third frequency band.

In FIG. 2A, filter circuit 12 is a lowpass filter having a passband thatis n77 (the first frequency band), an attenuation band that is n79 (thesecond frequency band), and an attenuation band that is the unlicensedband (the third frequency band). Filter circuit 11 is a highpass filterhaving a passband that is n79 and an attenuation band that is n77.Band-elimination filter circuit 13 is a filter circuit that changesbetween attenuating a signal of a partial band of the unlicensed band(activating the notch function) and not attenuating a signal of thepartial band (deactivating the notch function).

Note that filter circuit 12 may be a bandpass filter having a passbandthat is n77 (the first frequency band), an attenuation band that is n79(the second frequency band), and an attenuation band that is theunlicensed band (the third frequency band). Filter circuit 11 may be abandpass filter having a passband that is n79 and an attenuation bandthat is n77. Band-elimination filter circuit 13 may not be a notchfilter, and may be one of a highpass filter, a low pass filter, and abandpass filter that attenuates a signal of a partial band of theunlicensed band.

Accordingly, when n79 and the unlicensed band close to each other aresimultaneously used, high isolation between signals of n79 and theunlicensed band can be ensured by activating the notch function ofband-elimination filter circuit 13. When the unlicensed band is notsimultaneously used when n79 is used, the transfer loss of a radiofrequency signal of n79 can be reduced by deactivating the notchfunction of band-elimination filter circuit 13.

Note that in WLAN circuit 2A according to Variation 1 of Embodiment 1,filter circuit 21 is a filter having a passband that is the unlicensedband, for example. Band-elimination filter circuit 25 is a filtercircuit that changes between attenuating a signal of a partial band ofn79 (activating the notch function) and not attenuating a signal of thepartial band (deactivating the notch function).

Accordingly, when the unlicensed band and n79 close to each other aresimultaneously used, a high isolation between signals of the unlicensedband and n79 can be ensured by activating the notch function ofband-elimination filter circuit 25. When n79 is not simultaneously usedwhen the unlicensed band is used, a transfer loss of a radio frequencysignal of the unlicensed band can be reduced by deactivating the notchfunction of band-elimination filter circuit 25.

FIG. 2B illustrates a second example of communication bands and filterpassing characteristics applied to radio frequency module 1 according toEmbodiment 1 and Variation 1. In FIG. 2B, filter circuit 12 is a lowpassfilter having a passband that is n77, an attenuation band that is n79,and an attenuation band that is the unlicensed band. Filter circuit 11is a filter having a passband that is n79, an attenuation band that isn77, and an attenuation band that is the unlicensed band. Note thatfilter circuit 11 is an LC filter, and thus the amount of attenuation ofthe unlicensed band is smaller than the amount of attenuation of n77.Band-elimination filter circuit 13 changes between attenuating a signalof a partial band of the unlicensed band (activating the notch function)and not attenuating a signal of the partial band (deactivating the notchfunction).

Accordingly, when n79 and the unlicensed band close to each other areused simultaneously, the high isolation between n79 and the unlicensedband can be ensured by activating the notch function of band-eliminationfilter circuit 13. When the unlicensed band is not simultaneously usedwhen n79 is used, the transfer loss of a radio frequency signal of n79can be reduced by deactivating the notch function of band-eliminationfilter circuit 13. As compared with the passing characteristicsillustrated in FIG. 2A, filter circuit 11 further attenuates signals ofthe unlicensed band, and thus when n79 and the unlicensed band aresimultaneously used, the isolation between signals of n79 and theunlicensed band can be ensured more highly by deactivating the notchfunction of band-elimination filter circuit 13. On the other hand,filter circuit 11 attenuates a signal of the unlicensed band, and thus atransfer loss in the passband that is n79 is greater. Accordingly, whenthe unlicensed band is not simultaneously used when n79 is used, thetransfer loss of a radio frequency signal of n79 can be reduced bydeactivating the notch function of band-elimination filter circuit 13,but the transfer loss is greater as compared with the passingcharacteristics illustrated in FIG. 2A.

FIG. 2C illustrates a third example of communication bands and filterpassing characteristics applied to radio frequency module 1 according toEmbodiment 1 and Variation 1. In FIG. 2C, filter circuit 12 is a lowpassfilter having a passband that is n77, an attenuation band that is n79,and an attenuation band that is the unlicensed band. Filter circuit 11is a highpass filter having a passband that is n79 and an attenuationband that is n77. Out of UN1 (a third region) and UN2 (a fourth region)having a higher frequency range than UN1, which are partial bands of theunlicensed band, band-elimination filter circuit 13 changes betweenattenuating a signal of UN1 (activating the notch function) and notattenuating a signal of UN1 (deactivating the notch function).

Accordingly, when n79 and UN1 (the third region) of the unlicensed bandclose to each other are used simultaneously, the high isolation betweensignals of n79 and the unlicensed band can be ensured by activating thenotch function of band-elimination filter circuit 13. When theunlicensed band is not simultaneously used when n79 is used, thetransfer loss of a radio frequency signal of n79 can be reduced bydeactivating the notch function of band-elimination filter circuit 13.

Note that in band-elimination filter circuit 13, when UN1 having a lowerfrequency range of the unlicensed band is an attenuation band, thefrequency interval to n79 is relatively narrow, and thus the attenuationslope is to be made steep. Accordingly, band-elimination filter circuit13 desirably includes an acoustic wave resonator having a high resonanceQ factor.

Note that as the communication band applied to radio frequency module 1according to Embodiment 1 and Variation 1, filter circuit 12 may be alowpass filter having a passband that is NR-U (5.15 GHz to 5.35 GHz), anattenuation band that is NR-U (5.47 GHz to 5.85 GHz), and an attenuationband that is WLAN (5.925 GHz to 7.125 GHz). At this time, filter circuit11 may be a highpass filter having a passband that is NR-U (5.47 GHz to5.85 GHz) and an attenuation band that is NR-U (5.15 GHz to 5.35 GHz).At this time, band-elimination filter circuit 13 may change betweenattenuating a signal of at least a partial band of WLAN (5.925 GHz to7.125 GHz) (activating the notch function) and not attenuating a signalof the partial band (deactivating the notch function).

As a communication band applied to radio frequency module 1 according toEmbodiment 1 and Variation 1, filter circuit 12 may be a lowpass filterhaving a passband that is n77 or n79, an attenuation band that is NR-U(5.15 GHz to 5.85 GHz), and an attenuation band that is WLAN (5.925 GHzto 7.125 GHz). At this time, filter circuit 11 may be a highpass filterhaving a passband that is NR-U (5.15 GHz to 5.85 GHz), and anattenuation band that is n77 or n79. At this time, band-eliminationfilter circuit 13 may change between attenuating a signal of at least apartial band of WLAN (5.925 GHz to 7.125 GHz) (activating the notchfunction) and not attenuating a signal of the partial band (deactivatingthe notch function).

As a communication band applied to radio frequency module 1 according toEmbodiment 1 and Variation 1, filter circuit 12 may be a lowpass filterhaving a passband that is n77 or n79, an attenuation band that is NR-U(5.15 GHz to 5.35 GHz), and an attenuation band that is WLAN (5.47 GHzto 5.85 GHz).

At this time, filter circuit 11 may be a highpass filter having apassband that is NR-U (5.15 GHz to 5.35 GHz), and an attenuation bandthat is n77 or n79. Band-elimination filter circuit 13 may changebetween attenuating a signal of at least a partial band of WLAN (5.47GHz to 5.85 GHz) (activating the notch function) and not attenuating asignal of the partial band (deactivating the notch function).

FIG. 2D illustrates a fourth example of communication bands and filterpassing characteristics applied to radio frequency module 1 according toEmbodiment 1 and Variation 1. In FIG. 2D, filter circuit 12 is a lowpassfilter having a passband that is n77, an attenuation band that is n79,and an attenuation band that is the unlicensed band. Filter circuit 11is a highpass filter having a passband that is n79, and an attenuationband that is n77. Out of UN1 (the third region) and UN2 (the fourthregion) having a higher frequency range than UN1, which are partialbands of the unlicensed band, band-elimination filter circuit 13 changesbetween attenuating a signal of UN2 (activating the notch function) andnot attenuating a signal of UN2 (deactivating the notch function).

Accordingly, when n79 and UN2 (the fourth region) of the unlicensed bandclose to each other are used simultaneously, the high isolation betweensignals of n79 and the unlicensed band can be ensured by activating thenotch function of band-elimination filter circuit 13. When theunlicensed band is not simultaneously used when n79 is used, thetransfer loss of a radio frequency signal of n79 can be reduced bydeactivating the notch function of band-elimination filter circuit 13.

Note that in band-elimination filter circuit 13, when UN2 having ahigher frequency range of the unlicensed band is an attenuation band,the frequency interval to n79 is relatively wide as compared with UN1,and thus the attenuation slope may be made relatively gentle.Accordingly, band-elimination filter circuit 13 may not include anacoustic wave resonator. Moreover, when an acoustic wave resonator isnot included, the attenuation slope is gentle, yet a wide attenuationband can be ensured.

1.3 Example of Configuration of Band-Elimination Filter Circuit

FIGS. 3A to 3C illustrate a first example of a configuration ofband-elimination filter circuit 13 according to Embodiment 1. Asillustrated in FIG. 3B, band-elimination filter circuit 13 includesinductor 131 and capacitor 132 connected in series to a ground path thatconnects the ground and the second path that connects antenna terminal100 and input/output terminal 110, and switch 133 (a third switch)disposed on the ground path. Inductor 131 and capacitor 132 form an LCseries resonance circuit disposed on the ground path that is a parallelarm.

According to the above configuration, an impedance local minimum pointof the LC series resonance circuit is an attenuation pole, a signal of apartial band of the third frequency band is attenuated by placing switch133 into the conducting state, and a signal of the partial band of thethird frequency band is not attenuated by placing switch 133 into thenon-conducting state.

Note that in FIG. 3B, filter circuit 11 includes series-arm circuits 10a and 10 b disposed on the second path, inductor 131 and capacitor 132connected in series to the ground path, and switch 133 disposed on theground path. Thus, band-elimination filter circuit 13 is a portion offilter circuit 11. Note that band-elimination filter circuit 13 may beincluded in a circuit separate from filter circuit 11.

As illustrated in FIG. 3C, band-elimination filter circuit 13 includesinductor 131 and capacitor 132A connected in series to a ground paththat connects the ground and the second path that connects antennaterminal 100 and input/output terminal 110, capacitor 132B connectedbetween the ground and a connecting point of inductor 131 and capacitor132A, and switch 133 (a third switch) disposed on the ground path. Whenswitch 133 is conducting, inductor 131 and a parallel combined circuitof capacitors 132A and 132B form a first LC series resonance circuitdisposed on the ground path that is a parallel arm. When switch 133 isnon-conducting, inductor 131 and capacitor 132B form a second LC seriesresonance circuit disposed on the ground path that is a parallel arm.Here, a resonance frequency of the first LC series resonance circuit isdifferent from a resonance frequency of the second LC series resonancecircuit.

According to the above configuration, the impedance local minimum pointof the first LC series resonance circuit is an attenuation pole whenswitch 133 is conducting, and thus a signal of a first region of thethird frequency band can be attenuated, whereas the impedance localminimum point of the second LC series resonance circuit is anattenuation pole when switch 133 is non-conducting, and thus a signal ofa second region of the third frequency band different from the firstregion can be attenuated.

Note that in FIG. 3C, filter circuit 11 includes series-arm circuits 10a and 10 b disposed on the second path, inductor 131 and capacitor 132Aconnected in series to the ground path, capacitor 132B connected betweenthe ground and a connecting point of inductor 131 and capacitor 132A,and switch 133 disposed on the ground path. Thus, band-eliminationfilter circuit 13 is a portion of filter circuit 11. Note thatband-elimination filter circuit 13 may be included in a circuit separatefrom filter circuit 11.

Thus, band-elimination filter circuit 13 illustrated in FIG. 3B changesthe amount of attenuation of an attenuation band, and band-eliminationfilter circuit 13 illustrated in FIG. 3C can change the frequency rangeof an attenuation band.

Note that a circuit configuration of band-elimination filter circuit 13illustrated in FIG. 3B is applied to the passing characteristicsillustrated in FIG. 2D. Thus, the third frequency band belonging to theunlicensed band includes UN1 (the third region) and UN2 (the fourthregion), and when a radio frequency signal of n79 (the second frequencyband) and a radio frequency signal of UN2 (the fourth region) aresimultaneously transferred, switch 133 connects the second path,inductor 131, capacitor 132, and the ground.

Accordingly, when n79 and UN2 (the fourth region) of the unlicensed bandclose to each other are simultaneously used, the high isolation betweensignals of n79 and the unlicensed band can be ensured by placing switch133 into the conducting state. When the unlicensed band is notsimultaneously used when n79 is used, the transfer loss of a radiofrequency signal of n79 can be reduced by placing switch 133 into thenon-conducting state. Note that when UN2 having a higher frequency rangeof the unlicensed band is an attenuation band, the frequency interval ton79 is relatively wide as compared with UN1, and thus band-eliminationfilter circuit 13 may not include an acoustic wave resonator.

In band-elimination filter circuit 13 illustrated in FIG. 3B, a circuitconfiguration in which an acoustic wave resonator is disposed instead ofinductor 131 and capacitor 132 is applied to passing characteristicsillustrated in FIG. 2C. Thus, the third frequency band belonging to theunlicensed band includes UN1 (the third region) and UN2 (the fourthregion), and when a radio frequency signal of n79 (the second frequencyband) and a radio frequency signal of UN1 (the third region) aresimultaneously transferred, switch 133 connects the second path, theacoustic wave resonator, and the ground.

Accordingly, when n79 and UN1 (the third region) of the unlicensed bandclose to each other are simultaneously used, the high isolation betweensignals of n79 and the unlicensed band can be ensured by placing switch133 (the fourth switch) into the conducting state. When the unlicensedband is not simultaneously used when n79 is used, the transfer loss of aradio frequency signal of n79 can be reduced by placing switch 133 intothe non-conducting state. Note that when UN1 having a lower frequencyrange of the unlicensed band is an attenuation band, the frequencyinterval to n79 is relatively narrow, and thus the attenuation slope isto be made steep. Accordingly, band-elimination filter circuit 13includes an acoustic wave resonator having a high resonance Q factor.

FIG. 4A illustrates a circuit configuration of radio frequency module 1Aaccording to Variation 2 of Embodiment 1. As illustrated in FIG. 4A,radio frequency module 1A includes antenna terminal 100, input/outputterminals 110 and 120, filter circuits 11 and 12, band-eliminationfilter circuit 13A, switches 14, 15, 18, and 19, transmission amplifiers16T and 17T, and reception amplifiers 16R and 17R. Radio frequencymodule 1A according to this variation is different from radio frequencymodule 1 according to the embodiment, only in the configuration ofband-elimination filter circuit 13A. Accordingly, the followingdescribes radio frequency module 1A according to this variation,focusing on the configuration of band-elimination filter circuit 13A.

Band-elimination filter circuit 13A is an example of a firstband-elimination filter circuit, and includes band-elimination filter 31and switches 32 and 33.

Band-elimination filter 31 is an example of a first band-eliminationfilter, and is an attenuation-band fixed filter having an attenuationband that is a partial band of the third frequency band.

Each of switches 32 and 33 is an example of the first switch, andincludes a common terminal and two selection terminals. The commonterminal of switch 32 is connected to filter circuit 11, one selectionterminal out of the selection terminals of switch 32 is connected tobypass path 71 that connects antenna terminal 100 and input/outputterminal 110 and bypasses band-elimination filter 31, and the otherselection terminal of switch 32 is connected to band-elimination filter31. The common terminal of switch 33 is connected to switch 14, oneselection terminal out of the selection terminals of switch is connectedto bypass path 71, and the other selection terminal of switch 33 isconnected to band-elimination filter 31. This configuration allowsswitches 32 and 33 to switch the connection of antenna terminal 100between bypass path 71 and band-elimination filter 31. Note that atleast one of switch 32 or 33 may be disposed as the first switch.

According to the configuration of band-elimination filter circuit 13A,band-elimination filter 1A functions as a filter circuit that changesbetween attenuating a signal of a partial band of the unlicensed band(activating the notch function) and not attenuating a signal of thepartial band (deactivating the notch function).

FIG. 4B illustrates a circuit configuration of radio frequency module 1Baccording to Variation 3 of Embodiment 1. As illustrated in FIG. 4B,radio frequency module 1B includes antenna terminal 100, input/outputterminals 110 and 120, filter circuits 11 and 12, band-eliminationfilter circuit 13B, switches 14, 15, 18, and 19, transmission amplifiers16T and 17T, and reception amplifiers 16R and 17R. Radio frequencymodule 1B according to this variation is different from radio frequencymodule 1 according to the embodiment, only in the configuration ofband-elimination filter circuit 13B. Accordingly, the followingdescribes radio frequency module 1B according to this variation,focusing on the configuration of band-elimination filter circuit 13B.

Band-elimination filter circuit 13B is an example of a firstband-elimination filter circuit, and includes band-elimination filters34 and 35 and switches 32 and 33.

Band-elimination filter 34 is an example of a second band-eliminationfilter having an attenuation band that is the first region belonging tothe third frequency band, and is an attenuation-band fixed filter.Band-elimination filter 35 is an example of a third band-eliminationfilter having an attenuation band that is the second region belonging tothe third frequency band, and is an attenuation-band fixed filter. Notethat frequency ranges of the first region and the second region aredifferent.

Each of switches 32 and 33 is an example of a second switch, andincludes a common terminal and two selection terminals. The commonterminal of switch 32 is connected to filter circuit 11, one of theselection terminals of switch 32 is connected to band-elimination filter34, and the other selection terminal of switch 32 is connected toband-elimination filter 35. The common terminal of switch 33 isconnected to switch 14, one of the selection terminals of switch 33 isconnected to band-elimination filter 34, and the other selectionterminal of switch 33 is connected to band-elimination filter 35. Thisconfiguration allows switches 32 and 33 to switch the connection ofantenna terminal 100 between band-elimination filter 34 andband-elimination filter 35. Note that at least one of switch 32 or 33may be disposed as the second switch.

According to the configuration of band-elimination filter circuit 13B,radio frequency module 1B functions as a filter circuit that changes thefrequency range of the attenuation band in the unlicensed band.

FIG. 4C illustrates a circuit configuration of radio frequency module 1Caccording to Variation 4 of Embodiment 1. As illustrated in FIG. 4C,radio frequency module 1C includes antenna terminal 100, input/outputterminals 110 and 120, filter circuits 11 a, 11 b, and 12,band-elimination filter circuit 13C, switches 14, 15, 18, and 19,transmission amplifiers 16T and 17T, and reception amplifiers 16R and17R. Radio frequency module 1C according to this variation is differentfrom radio frequency module 1 according to the embodiment, in theconfigurations of filter circuits 11 a and 11 b and band-eliminationfilter circuit 13C. Accordingly, the following describes radio frequencymodule 1C according to this variation, focusing on the configurations offilter circuits 11 a and 11 b and band-elimination filter circuit 13C.

Band-elimination filter circuit 13C is an example of a firstband-elimination filter circuit, and includes band-elimination filter 36and switches 32 and 33.

Band-elimination filter 36 is an example of a first band-eliminationfilter, and is an attenuation-band fixed filter having an attenuationband that is a partial band of the third frequency band.

Each of switches 32 and 33 is an example of a first switch, and includesa common terminal and two selection terminals. The common terminal ofswitch 32 is connected to antenna terminal 100, one of the selectionterminals of switch 32 is connected to filter circuit 11 a, and theother selection terminal of switch 32 is connected to filter circuit 11b. The common terminal of switch 33 is connected to switch 14, one ofthe selection terminals of switch 33 is connected to bypass path 71 thatconnects antenna terminal 100 and input/output terminal 110 and bypassesband-elimination filter 31, and the other selection terminal of switch33 is connected to band-elimination filter 36. This configuration allowsswitches 32 and 33 to switch the connection of antenna terminal 100between bypasses path 71 and band-elimination filter 36. Note that atleast one of switch 32 or 33 may be disposed as the first switch.

Filter circuit 11 a is an example of a second filter circuit, and is ahighpass filter that is disposed between switch 32 and switch 33, isconnected to bypass path 71, and attenuates a signal of the firstfrequency band. Filter circuit 11 b is an example of a second filtercircuit, and is a band pass filter that is connected between switch 32and band-elimination filter 36, and attenuates a signal of the firstfrequency band and a signal of the third frequency band. Filter circuit11 a attenuates only a signal of a lower frequency range than thepassband, and filter circuit 11 b attenuates both of a signal of a lowerfrequency range and a signal of a higher frequency range than thepassband, and thus insertion loss in the passband of filter circuit 11 ais smaller than that of filter circuit 11 b.

According to the configuration of band-elimination filter circuit 13C,radio frequency module 1C functions as a filter circuit that changesbetween attenuating a signal of a partial band of the unlicensed band(activating the notch function) and not attenuating a signal of thepartial band (deactivating the notch function). When a radio frequencysignal of the second frequency band and a radio frequency signal of apartial band of the third frequency band are simultaneously used, thesignals pass through high-attenuation filter circuit 11 b operating asthe second filter circuit, and thus the amount of attenuation of thepartial band can be increased. On the other hand, when a radio frequencysignal of the second frequency band is used, and a radio frequencysignal of a partial band of the third frequency band is not used, thesignals pass through low-loss filter circuit 11 a operating as thesecond filter circuit, and thus a transfer loss of a radio frequencysignal of the second frequency band can be decreased.

1.4 Example of Configuration of First Filter Circuit and Second FilterCircuit

FIGS. 5A to 5C illustrate a circuit configuration of radio frequencymodule 1D according to Variation 5 of Embodiment 1. FIG. 5A illustratesfilter circuits 11D and 12D that are portions of the circuitconfiguration of radio frequency module 1D different from radiofrequency module 1 according to the embodiment. FIG. 5B illustrates afrequency relation of approximate passing characteristics tocommunication bands of filter circuits 11D and 12D. FIG. 5C illustratesan example of a circuit configuration of filter circuits 11D and 12D.

Radio frequency module 1D includes antenna terminal 100, input/outputterminals 110 and 120, filter circuits 11D and 12D, band-eliminationfilter circuit 13, switches 14, 15, 18, and 19, transmission amplifiers16T and 17T, and reception amplifiers 16R and 17R. As illustrated inFIG. 5A, radio frequency module 1D according to this variation isdifferent from radio frequency module 1 according to the embodiment,only in the configuration of filter circuit 11D that is a second filtercircuit and filter circuit 12D that is a first filter circuit. Thefollowing describes radio frequency module 1D, focusing on differentpoints from radio frequency module 1, while description of the samepoints is omitted.

Filter circuit 11D is an example of a second filter circuit, and is ahighpass filter having a variable passband that is the second frequencyband and a variable attenuation band. Filter circuit 12D is an exampleof the first filter circuit, and is a low pass filter having a variablepassband that is the first frequency band and a variable attenuationband.

Radio frequency module 1D according to this variation is used, forexample, when (1) a radio frequency signal of 4G-LTE B42 (3400 MHz to3600 MHz) belonging to the first frequency band and a radio frequencysignal of 5G-NR n79 (a “Low” band) belonging to the second frequencyband are simultaneously transferred, and (2) when a radio frequencysignal of 5G-NR n77 belonging to the first frequency band and a radiofrequency signal of 5G-NR n79 (a “High” band) belonging to the secondfrequency band are simultaneously transferred. The passbands and theattenuation bands of filter circuits 11D and 12D are varied according towhich of (1) and (2) above is performed. For example, when (1) above isperformed, the passband of filter circuit 11D and the passband of filtercircuit 12D shift to lower frequency ranges (the solid lines in FIG.5B). Accordingly, an isolation between a radio frequency signal of4G-LTE B42 and a radio frequency signal of 5G-NR n79 (a “Low” band) isensured, and the transfer loss can be reduced. For example, when (2)above is performed, the passband of filter circuit 11D and the passbandof filter circuit 12D shift to higher frequency ranges (the dashed linesin FIG. 5B). Accordingly, the isolation between a radio frequency signalof 5G-NR n77 and a radio frequency signal of 5G-NR n79 (a “High” band)is ensured, and the transfer loss can be reduced.

For example, a circuit configuration of filter circuits 11D and 12Dincludes an LC filter, as illustrated in FIG. 5C.

Filter circuit 11D includes capacitors 41 and 42 disposed on the secondpath that connects antenna terminal 100 and input/output terminal 110,and LC series resonance circuit 43 disposed between the second path andthe ground. LC series resonance circuit 43 includes one inductor, twocapacitors, and switch 44, and has a resonance frequency that variesaccording to switching of switch 44. This configuration allows filtercircuit 11D to form a highpass filter having a variable attenuationpole.

Filter circuit 12D includes inductors 51 and 52 disposed on the firstpath that connects antenna terminal 100 and input/output terminal 120,and LC series resonance circuit 53 disposed between the first path andthe ground. LC series resonance circuit 53 includes one inductor, twocapacitors, and switch 54, and has a resonance frequency that variesaccording to switching of switch 54. This configuration allows filtercircuit 12D to form a low pass filter having a variable attenuationpole.

FIGS. 6A to 6D illustrate circuit configurations of radio frequencymodule 1E according to Variation 6 of Embodiment 1. FIG. 6A illustratesfilter circuit 11E that is a portion of the circuit configuration ofradio frequency module 1E different from radio frequency module 1according to the embodiment. FIG. 6B illustrates a frequency relation ofapproximate passing characteristics to communication bands of filtercircuits 11E and 12. FIGS. 6C and 6D illustrate an example of a circuitconfiguration of filter circuit 11E.

Radio frequency module 1E includes antenna terminal 100, input/outputterminals 110 and 120, filter circuits 11E and 12, band-eliminationfilter circuit 13, switches 14, 15, 18, and 19, transmission amplifiers16T and 17T, and reception amplifiers 16R and 17R. As illustrated inFIG. 6A, radio frequency module 1E according to this variation isdifferent from radio frequency module 1 according to the embodiment,only in the configuration of filter circuit 11E that is a second filtercircuit. The following describes radio frequency module 1E, focusing ondifferent points from radio frequency module 1, while description of thesame points is omitted.

Filter circuit 11E is an example of a second filter circuit, and is ahighpass filter having a variable passband that is the second frequencyband and a variable attenuation slope. Note that an attenuation slope isan inclination of insertion loss from a lower frequency edge of apassband to an attenuation band having a lower frequency range, in thepassing characteristics of filter circuit 11E.

Radio frequency module 1E according to this variation is used (3) when aradio frequency signal of 5G-NR n77 belonging to the first frequencyband and a radio frequency signal of 5G-NR n79 (a “Low” band) belongingto the second frequency band are simultaneously transferred, and (4)when a radio frequency signal of 5G-NR n79 belonging to the secondfrequency band is transferred and a radio frequency signal of 5G-NR n77belonging to the first frequency band is not transferred, for example.The passband and the attenuation slope of filter circuit 11E varyaccording to which of (3) and (4) above is performed. For example, when(3) above is performed, the attenuation slopes of filter circuit 11E aresteep (the solid lines in FIG. 6B). Accordingly, the isolation between aradio frequency signal of 5G-NR n77 and a radio frequency signal of5G-NR n79 is ensured. For example, when (4) above is performed, theattenuation slope of filter circuit 11E is gentle (the dashed line inFIG. 6B). Thus, the transfer loss of a radio frequency signal of a lowerfrequency range in the passband that is 5G-NR n79 can be reduced.

For example, a circuit configuration of filter circuit 11E includes anLC filter that includes acoustic wave resonator 11 p 1, as illustratedin FIG. 6C. Filter circuit 11E includes series-arm circuits 11 s 1 and11 s 2 disposed on the second path that connects antenna terminal 100and input/output terminal 110, acoustic wave resonator 11 p 1 disposedbetween the second path and the ground, parallel-arm circuits 11 p 2 and11 p 3, and switch SW1. Series-arm circuits 11 s 1 and 11 s 2 andparallel-arm circuits 11 p 2 and 11 p 3 each include at least one of aninductor or a capacitor. Acoustic wave resonator 11 p 1 and a seriesconnection circuit of parallel-arm circuit 11 p 3 and switch SW1 areconnected in parallel. When switch SW1 is conducting, the attenuationslope of filter circuit 11E is determined by the Q factor ofparallel-arm circuit 11 p 3 mainly, and is gentle. On the other hand,when switch SW1 is non-conducting, the attenuation slope of filtercircuit 11E is determined by the Q factor of acoustic wave resonator 11p 1 mainly, and is steep. Accordingly, filter circuit 11E forms ahighpass filter having a variable passband and a variable attenuationslope. Note that series-arm circuits 11 s 1 and 11 s 2 and parallel-armcircuits 11 p 2 and 11 p 3 may not each include an inductor or acapacitor, and may each include only a line.

For example, a circuit configuration of filter circuit 11E includes anLC filter that includes acoustic wave resonator 11 p 1, as illustratedin FIG. 6D. Filter circuit 11E includes series-arm circuits 11 s 1 and11 s 2 disposed on the second path that connects antenna terminal 100and input/output terminal 110, and acoustic wave resonator 11 p 1,parallel-arm circuit 11 p 2, and switch SW2 that are disposed betweenthe second path and the ground. Series-arm circuits 11 s 1 and 11 s 2and parallel-arm circuit 11 p 2 each include at least one of an inductoror a capacitor. Acoustic wave resonator 11 p 1, parallel-arm circuit 11p 2, and switch SW2 are connected in series. When switch SW2 isconducting, the attenuation slope of filter circuit 11E is determined bythe Q factors of acoustic wave resonator 11 p 1 and parallel-arm circuit11 p 2, and is steep. On the other hand, when switch SW2 isnon-conducting, the attenuation slope of filter circuit 11E is notdetermined by the Q factor of acoustic wave resonator 11 p 1, and isgentle. Accordingly, filter circuit 11E forms a highpass filter having avariable passband and a variable attenuation slope. Note that series-armcircuits 11 s 1 and 11 s 2 and parallel-arm circuits 11 p 2 and 11 p 3may each include only a line without including an inductor or acapacitor.

Note that as illustrated in FIGS. 5A to 5C, a second filter circuit(filter circuit 11D) and a first filter circuit (filter circuit 12D) mayboth have variable passbands, or as illustrated in FIGS. 6A to 6D, onlyone of the second filter circuit (filter circuit 11E) and the firstfilter circuit (filter circuit 12) may have a variable passband.

Embodiment 2

Radio frequency module 1F according to the present embodiment includes acircuit that transfers a radio frequency signal of a third frequencyband (an unlicensed band ranging from 5 GHz or higher), in addition to acircuit that transfers radio frequency signals of a first frequency bandand a second frequency band.

2.1 Configuration of Radio Frequency Module 1F and Communication Device7F

FIG. 7 illustrates a circuit configuration of radio frequency module 1Fand communication device 7F according to Embodiment 2. As illustrated inFIG. 7 , communication device 7F includes radio frequency module 1F,RFICs 3 and 4, BBIC 5, and antenna 61. Communication device 7F accordingto the present embodiment is different from communication device 7according to Embodiment 1, in that WLAN circuit 2 is included in radiofrequency module 1F, and a single antenna is included. The followingdescribes communication device 7F according to the present embodiment,focusing on differences from communication device 7 according toEmbodiment 1.

Antenna 61 radiates and receives radio frequency signals of the firstfrequency band, the second frequency band, and the third frequency band.

Note that in the present embodiment, the second frequency bandcorresponds to a communication band close to the lowest frequency of theunlicensed band ranging from 5 GHz or higher, and is a communicationband of 4G-LTE or 5G-NR, for example. In particular, the secondfrequency band is, for example, 5G-NR n79 whose frequency interval tothe unlicensed band is narrow. In the present embodiment, the firstfrequency band corresponds to a communication band close to the lowestfrequency of the second frequency band, and is, for example, acommunication band of 4G-LTE or 5G-NR. In particular, the firstfrequency band is 5G-NR n77, for example. In the present embodiment, thethird frequency band corresponds to a communication band belonging tothe unlicensed band ranging from 5 GHz or higher. The third frequencyband is WLAN (Wi-Fi®), B46 of LAA, or NR-U, for example.

Radio frequency module 1F includes antenna terminal 100, input/outputterminals 110, 120, and 210, filter circuits 11, 12, and 21,band-elimination filter circuit 13, switches 14, 15, 18, 19, 22, and 24,transmission amplifiers 16T, 17T, and 23T, and reception amplifiers 16R,17R, and 23R.

Antenna terminal 100 is connected to antenna 61.

Filter circuit 21 is an example of a third filter circuit, and is afilter disposed on a path that connects antenna terminal 200 andinput/output terminal 210, and having a passband that is the thirdfrequency band.

In the present embodiment, filter circuits 11, 12, and 21 are directlyconnected to antenna terminal 100. That is, filter circuits 11, 12, and21 form a triplexer that demultiplexes and multiplexes a radio frequencysignal of the first frequency band, a radio frequency signal of thesecond frequency band, and a radio frequency signal of the thirdfrequency band.

Note that filter circuits 11, 12, and 21 may not be directly connectedto antenna terminal 100. In this case, a switch that switches betweenthe connection and disconnection of antenna terminal 100 to/from filtercircuit 11, switches between the connection and disconnection of antennaterminal 100 to/from filter circuit 12, and switches between theconnection and disconnection of antenna terminal 100 to/from filtercircuit 21 may be disposed between antenna terminal 100 and filtercircuits 11, 12, and 21.

According to the above configuration of radio frequency module 1Faccording to the present embodiment, the same effects as those yieldedby radio frequency module 1 according to Embodiment 1 can be produced.Furthermore, the number of disposed antennas included in communicationdevice 7F can be reduced.

2.2 Communication Bands and Filter Passing Characteristics Applied toRadio Frequency Module 1F

FIG. 8 illustrates an example of communication bands and filter passingcharacteristics applied to radio frequency module 1F according toEmbodiment 2. 5G-NR n77, for example, is applied as the first frequencyband, 5G-NR n79, for example, is applied as the second frequency band,and WLAN (Wi-Fi®) of the unlicensed band, B46 of LAA, or NR-U, forexample, is applied as the third frequency band.

In FIG. 8 , filter circuit 12 is a lowpass filter having a passband thatis n77, an attenuation band that is n79, and an attenuation band that isthe unlicensed band. Filter circuit 11 is a highpass filter having apassband that is n79 and an attenuation band that is n77.Band-elimination filter circuit 13 is a filter circuit that changesbetween attenuating a signal of a partial band of the unlicensed band(activating the notch function) and not attenuating a signal of thepartial band (deactivating the notch function).

Filter circuit 21 is a highpass filter having a passband that is afrequency range of WLAN (Wi-Fi®) of the unlicensed band, an attenuationband that is n77, and an attenuation band that is n79, for example.

Accordingly, when n79 and the unlicensed band close to each other aresimultaneously used, a high isolation between signals of n79 and theunlicensed band can be ensured by activating the notch function ofband-elimination filter circuit 13. When the unlicensed band is notsimultaneously used when n79 is used, the transfer loss of a radiofrequency signal of n79 can be reduced by deactivating the notchfunction of band-elimination filter circuit 13.

Embodiment 3

Radio frequency module 1G according to the present embodiment includes acircuit that transfers a radio frequency signal of a second frequencyband close to an unlicensed band.

3.1 Configuration of Radio Frequency Module 1G and Communication Device7G

FIG. 9A illustrates a circuit configuration of radio frequency module 1Gand communication device 7G according to Embodiment 3. As illustrated inFIG. 9A, communication device 7G includes radio frequency module 1G,WLAN circuit 2, RFICs 3 and 4, BBIC 5, and antennas 61 and 62.Communication device 7G according to the present embodiment is differentfrom communication device 7 according to Embodiment 1, in that a circuitthat transfers a radio frequency signal of a first frequency band is notincluded. The following describes communication device 7G according tothe present embodiment, focusing on differences from communicationdevice 7 according to Embodiment 1.

Antenna 61 radiates and receives radio frequency signals of the secondfrequency band. Antenna 62 radiates and receives radio frequency signalsof a third frequency band.

Radio frequency module 1G includes antenna terminal 100, input/outputterminal 130, filter circuit 11, band-elimination filter circuit 13,switches 14 and 15, transmission amplifier 16T, and reception amplifier16R.

Antenna terminal 100 is connected to antenna 61.

Filter circuit 11 is an example of a second filter circuit, and is afilter that is disposed on a second path that connects antenna terminal100 and input/output terminal 130 (a second input/output terminal), hasa passband that is the second frequency band, and attenuates a signal ofthe first frequency band lower or higher than the second frequency band.Filter circuit 11 is a so-called LC filter that includes an inductor anda capacitor.

Band-elimination filter circuit 13 is an example of a firstband-elimination filter circuit, and is a band-elimination filter thatis disposed on the second path, and has an attenuation band that is apartial band of the third frequency band that belongs to an unlicensedband ranging from 5 GHz or higher and is higher or lower than the secondfrequency band. Band-elimination filter circuit 13 changes at least oneof a frequency range or an amount of attenuation of the attenuationband.

Note that in band-elimination filter circuit 13, the frequency range orthe amount of attenuation of the attenuation band may be fixed(alternatively, may not be changed).

WLAN circuit 2 includes antenna terminal 200, input/output terminal 210,filter circuit 21, switches 22 and 24, transmission amplifier 23T, andreception amplifier 23R.

Antenna terminal 200 is connected to antenna 62.

Filter circuit 21 is an example of a third filter circuit, and is afilter disposed on a third path that connects antenna terminal 200 andinput/output terminal 210, and having a passband that is the thirdfrequency band.

Note that WLAN circuit 2 may be included in radio frequency module 1G.

FIG. 9B illustrates a circuit configuration of radio frequency module 1Gand communication device 7H according to a variation of Embodiment 3. Asillustrated in FIG. 9B, communication device 7H includes radio frequencymodule 1G, WLAN circuit 2H, RFICs 3 and 4, BBIC 5, and antennas 61 and62. Communication device 7H according to this variation is differentfrom communication device 7G according to Embodiment 3 in theconfiguration of WLAN circuit 2H. The following describes communicationdevice 7H according to this variation, focusing on differences fromcommunication device 7G according to Embodiment 3.

WLAN circuit 2H includes antenna terminal 200, input/output terminal210, filter circuit 21, band-elimination filter circuit 25, switches 22and 24, transmission amplifier 23T, and reception amplifier 23R.

Antenna terminal 200 is connected to antenna 62.

Filter circuit 21 is an example of a third filter circuit, and is afilter disposed on the third path that connects antenna terminal 200 andinput/output terminal 210, and having a passband that is the thirdfrequency band.

Band-elimination filter circuit 25 is an example of a secondband-elimination filter circuit, and is a band-elimination filterdisposed on the third path and having an attenuation band that is apartial band of the second frequency band. Band-elimination filtercircuit 25 changes at least one of a frequency range or an amount ofattenuation of the attenuation band.

Note that in band-elimination filter circuit 25, the frequency range andthe amount of attenuation of the attenuation band may be fixed(alternatively, may not be changed).

Note that WLAN circuit 2H may be included in radio frequency module 1G.

3.2 Communication Bands and Filter Passing Characteristics Applied toRadio Frequency Module 1G

FIG. 10A illustrates a first example of filter passing characteristicsof radio frequency module 1G according to Embodiment 3 and the variationthereof. 5G-NR n79, for example, is applied as the second frequencyband, and WLAN (Wi-Fi®) of the unlicensed band, for example, is appliedas the third frequency band.

In FIG. 10A, filter circuit 11 is a highpass filter that has a passbandthat is n79, and attenuates a signal of n77 that is the first frequencyband. Band-elimination filter circuit 13 changes between attenuating asignal of a partial band of WLAN (Wi-Fi®) (activating the notchfunction) and not attenuating a signal of the partial band (deactivatingthe notch function).

Accordingly, when n79 and the unlicensed band close to each other aresimultaneously used, a high isolation between signals of n79 and theunlicensed band can be ensured by activating the notch function ofband-elimination filter circuit 13. When the unlicensed band is notsimultaneously used when n79 is used, transfer loss of a radio frequencysignal of n79 can be reduced by deactivating the notch function ofband-elimination filter circuit 13.

Note that in WLAN circuit 2H according to the variation of Embodiment 3,filter circuit 21 is a filter having a passband that is WLAN (Wi-Fi®),for example. Band-elimination filter circuit 25 changes betweenattenuating a signal of a partial band of n79 (activating the notchfunction) and not attenuating a signal of the partial band (deactivatingthe notch function), for example.

Accordingly, when WLAN (®) and n79 that are close to each other aresimultaneously used, a high isolation between signals of WLAN (Wi-Fi®)and n79 can be ensured by activating the notch function ofband-elimination filter circuit 25. When n79 is not simultaneously usedwhen WLAN (Wi-Fi®) is used, transfer loss of a radio frequency signal ofWLAN (Wi-Fi®) can be reduced by deactivating the notch function ofband-elimination filter circuit 25.

In radio frequency module 1G according to Embodiment 3 and the variationthereof, filter circuit 11 may be a highpass filter that has a passbandthat is NR-U (5.15 GHz to 5.85 GHz), and attenuates a signal of thefirst frequency band. At this time, band-elimination filter circuit 13may be a filter circuit that changes between attenuating a signal of apartial band of WLAN (5.925 GHz to 7.125 GHz) (activating the notchfunction) and not attenuating a signal of the partial band (deactivatingthe notch function).

FIG. 10B illustrates a second example of filter passing characteristicsof radio frequency module 1G according to Embodiment 3 and the variationthereof. A frequency range included in the band from 7 GHz to 24 GHz,for example, is applied as the second frequency band, and WLAN (Wi-Fi®)of the unlicensed band, for example, is applied as the third frequencyband.

In FIG. 10B, filter circuit 11 is a lowpass filter that has a passbandthat is the second frequency band included in the band from 7 GHz to 24GHz, and attenuates a signal of the first frequency band higher than thesecond frequency band. Band-elimination filter circuit 13 changesbetween attenuating a signal of a partial band of WLAN (Wi-Fi®)(activating the notch function) and not attenuating a signal of thepartial band (deactivating the notch function).

Accordingly, when the second frequency band in the band from 7 GHz to 24GHz and the unlicensed band that are close to each other are usedsimultaneously, the high isolation between the second frequency band andthe unlicensed band can be ensured by activating the notch function ofband-elimination filter circuit 13. When the unlicensed band is notsimultaneously used when the second frequency band is used, transferloss of a radio frequency signal of the second frequency band can bereduced by deactivating the notch function of band-elimination filtercircuit 13.

Note that in WLAN circuit 2H according to the variation of Embodiment 3,filter circuit 21 is a filter having a passband that is WLAN (Wi-Fi®),for example. Band-elimination filter circuit 25 changes betweenattenuating a signal of a partial band of the band from 7 GHz to 24 GHz(activating the notch function) and not attenuating a signal of thepartial band (deactivating the notch function).

Accordingly, when WLAN (Wi-Fi®) and a communication band belonging tothe band from 7 GHz to 24 GHz, which are close to each other, are usedsimultaneously, the high isolation between signals of WLAN (Wi-Fi®) andthe communication band belonging to the band from 7 GHz to 24 GHz can beensured by activating the notch function of band-elimination filtercircuit 25. When a communication band belonging to the band from 7 GHzto 24 GHz is not used simultaneously when WLAN (Wi-Fi®) is used,transfer loss of a radio frequency signal of WLAN (Wi-Fi®) can bereduced by deactivating the notch function of band-elimination filtercircuit 25.

In radio frequency module 1G according to Embodiment 3 and the variationthereof, filter circuit 11 may be a lowpass filter that has a passbandthat is the second frequency band included in NR-U (5.925 GHz to 7.125GHz), and attenuates a signal of the first frequency band higher thanthe second frequency band. At this time, band-elimination filter circuit13 may be a filter circuit that changes between attenuating a signal ofa partial band of WLAN (5.15 GHz to 5.85 GHz) (activating the notchfunction) and not attenuating a signal of the partial band (deactivatingthe notch function).

As described above, radio frequency module 1 according to Embodiment 1includes: antenna terminal 100; input/output terminal 110; input/outputterminal 120; filter circuit 12 disposed on a first path and having apassband that is a first frequency band, the first path connectingantenna terminal 100 and input/output terminal 120; filter circuit 11disposed on a second path and having a passband that is a secondfrequency band higher than the first frequency band, the second pathconnecting antenna terminal 100 and input/output terminal 110; andband-elimination filter circuit 13 disposed on the second path andhaving an attenuation band that is a partial band of a third frequencyband belonging to an unlicensed band that ranges from 5 GHz or higher,the third frequency band being higher than the second frequency band.Filter circuit 11 is an LC filter circuit that includes an inductor anda capacitor.

According to this, filter circuit 11 that passes a signal of the secondfrequency band is formed with an LC filter, and thus the passband offilter circuit 11 can be increased. Although filter circuit 11 can usethe first frequency band as an attenuation band, filter circuit 11 is anLC filter, and thus cannot fully ensure the amount of attenuation of thethird frequency band. To address this, band-elimination filter circuit13 having an attenuation band that is a partial band of the thirdfrequency band is disposed on the second path. Accordingly, the highisolation can be ensured when the second frequency band and the thirdfrequency band close to each other are simultaneously used.Specifically, it is possible to provide radio frequency module 1 thatcan reduce deterioration of communication quality when a radio frequencysignal of the unlicensed band ranging from 5 GHz or higher and a wideband close to the unlicensed band are simultaneously used.

In radio frequency module 1, band-elimination filter circuit 13 may beconfigured to change at least one of a frequency range of theattenuation band or an amount of attenuation of the attenuation band.

According to this, according to whether a radio frequency signal of thesecond frequency band is used simultaneously with a radio frequencysignal of the third frequency band, band-elimination filter circuit 13can change at least one of the frequency range or the amount ofattenuation of the third frequency band. Furthermore, according to apartial band of the third frequency band of a radio frequency signalused simultaneously with a radio frequency signal of the secondfrequency band, band-elimination filter circuit 13 changes at least oneof the frequency range or the amount of attenuation of the partial band.A circuit configuration that highly attenuates a signal of the thirdfrequency band is not added to filter circuit 11, and low loss of thepassband is ensured, and thus when the second frequency band is not usedsimultaneously with the third frequency band, transfer loss of a radiofrequency signal of the second frequency band can be reduced by notallowing band-elimination filter circuit 13 to operate.

In radio frequency module 1A, band-elimination filter circuit 13A mayinclude: band-elimination filter 31 having an attenuation band that isthe partial band; and switches 32 and 33 configured to controllablyswitch the connection of antenna terminal 100 between bypass path 71 andband-elimination filter 31, bypass path 71 bypassing band-eliminationfilter 31 and connecting antenna terminal 100 and input/output terminal110.

Accordingly, band-elimination filter circuit 13A can function as afilter circuit that changes between attenuating a signal of a partialband of the third frequency band (activating the notch function) and notattenuating a signal of the partial band (deactivating the notchfunction).

In radio frequency module 1A, under a condition that a radio frequencysignal of the second frequency band and a radio frequency signal of thepartial band are simultaneously transferred, switches 32 and 33 may beconfigured to connect antenna terminal 100 to band-elimination filter31.

Accordingly, the isolation when a radio frequency signal of the secondfrequency band and a radio frequency signal of the partial band aresimultaneously transferred can be improved.

In radio frequency module 1C, filter circuit 11 b may be connectedbetween switch 32 and band-elimination filter 36, and may be configuredto attenuate a signal of the first frequency band and a signal of thethird frequency band.

Accordingly, band-elimination filter circuit 13C can function as afilter circuit that changes between attenuating a signal of a partialband of the third frequency band (activating the notch function) and notattenuating a signal of the partial band (deactivating the notchfunction). When a radio frequency signal of the second frequency bandand a radio frequency signal of a partial band of the third frequencyband are simultaneously used, the signals pass through high-attenuationfilter circuit 11 b, and thus the amount of attenuation of the partialband can be increased. On the other hand, when a radio frequency signalof the second frequency band is used, and a radio frequency signal of apartial band of the third frequency band is not used, the signals passthrough low-loss filter circuit 11 a, and thus transfer loss of a radiofrequency signal of the second frequency band can be decreased.

In radio frequency module 1B, band-elimination filter circuit 13B mayinclude: band-elimination filter 34 having an attenuation band that is afirst region belonging to the third frequency band; band-eliminationfilter 35 having an attenuation band that is a second region belongingto the third frequency band; and switches 32 and 33 configured tocontrollably switch the connection of filter circuit 11 betweenband-elimination filter 34 and band-elimination filter 35.

Accordingly, band-elimination filter circuit 13B can function as afilter circuit that varies the frequency range of the attenuation bandin the third frequency band.

In radio frequency module 1, filter circuit 12 and filter circuit 11 maybe directly connected to antenna terminal 100.

Accordingly, filter circuits 11 and 12 are included in a diplexer thatdemultiplexes and multiplexes a radio frequency signal of the firstfrequency band and a radio frequency signal of the second frequencyband, and thus radio frequency module 1 is further miniaturized.

Radio frequency module 1F according to Embodiment 2 may further include:filter circuit 21 having a passband that is the third frequency band, inaddition to filter circuits 11 and 12 and band-elimination filtercircuit 13.

Accordingly, it is possible to provide radio frequency module 1F thatcan reduce deterioration of communication quality when a radio frequencysignal of the unlicensed band ranging from 5 GHz or higher and a wideband close to the unlicensed band are simultaneously used. Furthermore,the number of disposed antennas included in communication device 7F canbe reduced.

Radio frequency module 1 may further include: band-elimination filtercircuit 25 disposed on a third path and having an attenuation band thatis a partial band of the second frequency band, the third path being apath on which filter circuit 21 is disposed.

Accordingly, the high isolation in the third path can be ensuredaccording to the state of simultaneously using the third frequency bandand the second frequency band close to each other.

Band-elimination filter circuit 13 may include: inductor 131 andcapacitor 132 connected in series to a ground path that connects thesecond path and a ground; and switch 133 disposed on the ground path.

Accordingly, the impedance local minimum point of an LC series resonantcircuit that includes inductor 131 and capacitor 132 can be anattenuation pole, a signal of a partial band of the third frequency bandcan be attenuated by placing switch 133 into the conducting state, and asignal of the partial band of the third frequency band can be preventedfrom being attenuated by placing switch 133 into the non-conductingstate.

The third frequency band may include a third region and a fourth region,the fourth region having a higher frequency range than the third region,and under a condition that a radio frequency signal of the secondfrequency band and a radio frequency signal of the fourth region aresimultaneously transferred, switch 133 may be configured to connect thesecond path, inductor 131, capacitor 132, and the ground.

Accordingly, when the second frequency band and the fourth region of thethird frequency band close to each other are used simultaneously, thehigh isolation between the second frequency band and the third frequencyband can be ensured by placing switch 133 into the conducting state.When the fourth region is not simultaneously used when the secondfrequency band is used, transfer loss of a radio frequency signal of thesecond frequency band can be decreased by placing switch 133 into thenon-conducting state. Note that if the fourth region is an attenuationband, a frequency interval between the fourth region and the secondfrequency band is relatively wide as compared with a frequency intervalbetween the third region and the second frequency band, and thusband-elimination filter circuit 13 may not include an acoustic waveresonator.

Band-elimination filter circuit 13 may include: an acoustic waveresonator connected in series to a ground path that connects the secondpath and a ground; and switch 133 disposed on the ground path.

Accordingly, when the second frequency band and the third region of thethird frequency band close to each other are simultaneously used, highisolation between signals of the second frequency band and the thirdfrequency band can be ensured by placing switch 133 into the conductingstate. When the fourth region is not simultaneously used when the secondfrequency band is used, transfer loss of a radio frequency signal of thesecond frequency band can be decreased by placing switch 133 into thenon-conducting state. Note that when the third region is an attenuationband, a frequency interval between the third region and the secondfrequency band is relatively narrow, and thus the attenuation slope ofband-elimination filter circuit 13 is to be made steep. Accordingly,band-elimination filter circuit 13 includes an acoustic wave resonatorhaving a high resonance Q factor.

At least one of the passband of filter circuit 12 or the passband offilter circuit 11 may be variable.

Accordingly, even if a combination of the second frequency band and thethird frequency band that are simultaneously used is changed, isolationbetween a radio frequency signal of the second frequency band and aradio frequency signal of the third frequency band can be ensured, andtransfer loss can be decreased.

Filter circuit 11 may include a capacitive series-arm circuit disposedon the second path, band-elimination filter circuit 13 may include acapacitive series-arm circuit and one or more parallel-arm circuits, thecapacitive series-arm circuit being disposed on the second path, and thecapacitive series-arm circuit of filter circuit 11 and the capacitiveseries-arm circuit of band-elimination filter circuit 13 may be directlyconnected.

Accordingly, the impedance between filter circuit 11 andband-elimination filter circuit 13 can be readily matched, and a radiofrequency signal of the second frequency band can be transferred throughthe second path while loss is kept low.

Radio frequency module 1G according to Embodiment 3 includes: antennaterminal 100; input/output terminal 130; filter circuit 11 disposed on asecond path, having a passband that is a second frequency band, andconfigured to attenuate a signal of a first frequency band, the secondpath connecting antenna terminal 100 and input/output terminal 130, thefirst frequency band being lower than the second frequency band; andband-elimination filter circuit 13 disposed on the second path andhaving an attenuation band that is a partial band of a third frequencyband belonging to an unlicensed band that ranges from 5 GHz or higher,the third frequency band being higher than the second frequency band.Filter circuit 11 is an LC filter circuit that includes an inductor anda capacitor, and band-elimination filter circuit 13 is configured tochange at least one of a frequency range of the attenuation band or anamount of attenuation of the attenuation band.

Accordingly, when the second frequency band and the third frequency bandclose to each other are simultaneously used, high isolation betweensignals of the second frequency band and the third frequency band can beensured by activating the notch function of band-elimination filtercircuit 13. When the third frequency band is not simultaneously usedwhen the second frequency band is used, transfer loss of a radiofrequency signal of the second frequency band can be decreased bydeactivating the notch function of band-elimination filter circuit 13.

Radio frequency module 1G according to Embodiment 3 includes: antennaterminal 100; input/output terminal 130; filter circuit 11 disposed on asecond path, having a passband that is a second frequency band, andconfigured to attenuate a signal of a first frequency band, the secondpath connecting antenna terminal 100 and input/output terminal 130, thefirst frequency band being higher than the second frequency band; andband-elimination filter circuit 13 disposed on the second path andhaving an attenuation band that is a partial band of a third frequencyband belonging to an unlicensed band that ranges from 5 GHz or higher,the third frequency band being lower than the second frequency band.Filter circuit 11 is an LC filter circuit that includes an inductor anda capacitor, and band-elimination filter circuit 13 is configured tochange at least one of a frequency range of the attenuation band or anamount of attenuation of the attenuation band.

Accordingly, when the second frequency band and the third frequency bandclose to each other are simultaneously used, high isolation between thesecond frequency band and the third frequency band can be ensured byactivating the notch function of band-elimination filter circuit 13.When the third frequency band is not simultaneously used when the secondfrequency band is used, transfer loss of a radio frequency signal of thesecond frequency band can be decreased by deactivating the notchfunction of band-elimination filter circuit 13.

Radio frequency module 1G may further include: filter circuit 21disposed on a third path and having a passband that is the thirdfrequency band; and band-elimination filter circuit 25 disposed on thethird path and having an attenuation band that is a partial band of thesecond frequency band.

Accordingly, high isolation in the third path can be ensured accordingto the state of simultaneously using the third frequency band and thesecond frequency band close to each other.

Communication device 7 includes: antennas 61 and 62; RFIC 3 configuredto process radio frequency signals to be transmitted by antennas 61 and62 and radio frequency signals received by antennas 61 and 62; and radiofrequency module 1 configured to transfer the radio frequency signalsbetween antenna 61 and RFIC 3.

Accordingly, it is possible to provide communication device 7 that canreduce deterioration of communication quality when a radio frequencysignal of the unlicensed band ranging from 5 GHz or higher and a wideband close to the unlicensed band are simultaneously used.

4. Other Embodiments

The above has described the radio frequency module and the communicationdevice according to the present disclosure, using the embodiments andthe variations thereof, yet the present disclosure is not limited to theembodiments and the variations. The present disclosure also encompassesanother embodiment achieved by combining arbitrary elements in theembodiments and the variations, and variations as a result of applying,to the embodiments, various modifications that may be conceived by thoseskilled in the art without departing from the scope of the presentdisclosure, and various devices that include the radio frequency moduleand the communication device according to the present disclosure.

For example, in the radio frequency module and the communication deviceaccording to the above embodiments and variations, matching elementssuch as an inductor and a capacitor and a switch circuit may beconnected between elements. Note that the inductor may include a lineinductor achieved by a line that connects elements.

Although only some exemplary embodiments of the present disclosure havebeen described in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of the present disclosure. Accordingly, all suchmodifications are intended to be included within the scope of thepresent disclosure.

The present disclosure can be widely used in communication apparatusessuch as mobile phones, as a radio frequency module and a communicationdevice that are applicable to a multi-band system including anunlicensed band ranging from 5 GHz or higher.

The invention claimed is:
 1. A radio frequency module, comprising: anantenna terminal; a first input/output terminal; a second input/outputterminal; a first filter circuit disposed on a first path and having apassband that is a first frequency band, the first path connecting theantenna terminal and the first input/output terminal; a second filtercircuit disposed on a second path and having a passband that is a secondfrequency band higher than the first frequency band, the second pathconnecting the antenna terminal and the second input/output terminal;and a first band-elimination filter circuit disposed on the second pathand having an attenuation band that is a partial band of a thirdfrequency band belonging to an unlicensed band, the third frequency bandbeing higher than the second frequency band.
 2. The radio frequencymodule according to claim 1, wherein the first band-elimination filtercircuit is configured to change at least one of a frequency range of theattenuation band or an amount of attenuation of the attenuation band. 3.The radio frequency module according to claim 1, wherein the firstband-elimination filter circuit includes: a first band-eliminationfilter having an attenuation band that is the partial band of the thirdfrequency band; and a first switch configured to controllably switch aconnection of the antenna terminal between a bypass path and the firstband-elimination filter, the bypass path bypassing the firstband-elimination filter and connecting the antenna terminal and thesecond input/output terminal.
 4. The radio frequency module according toclaim 3, wherein under a condition that a radio frequency signal of thesecond frequency band and a radio frequency signal of the partial bandof the third frequency band are simultaneously transferred, the firstswitch is configured to connect the antenna terminal to the firstband-elimination filter.
 5. The radio frequency module according toclaim 3, wherein the second filter circuit is connected between thefirst switch and the first band-elimination filter, and is configured toattenuate a signal of the first frequency band and a signal of the thirdfrequency band.
 6. The radio frequency module according to claim 1,wherein the first band-elimination filter circuit includes: a secondband-elimination filter having an attenuation band that is a firstregion belonging to the third frequency band; a third band-eliminationfilter having an attenuation band that is a second region belonging tothe third frequency band; and a second switch configured to controllablyswitch a connection of the second filter circuit between the secondband-elimination filter and the third band-elimination filter.
 7. Theradio frequency module according to claim 1, wherein the first filtercircuit and the second filter circuit are directly connected to theantenna terminal.
 8. The radio frequency module according to claim 1,further comprising: a third filter circuit having a passband that is thethird frequency band.
 9. The radio frequency module according to claim8, further comprising: a second band-elimination filter circuit disposedon a third path and having an attenuation band that is a partial band ofthe second frequency band, the third path being a path on which thethird filter circuit is disposed.
 10. The radio frequency moduleaccording to claim 1, wherein the first band-elimination filter circuitincludes: an inductor and a capacitor connected in series to a groundpath that connects the second path and a ground; and a third switchdisposed on the ground path.
 11. The radio frequency module according toclaim 10, wherein the third frequency band includes a third region and afourth region, the fourth region having a higher frequency range thanthe third region, and under a condition that a radio frequency signal ofthe second frequency band and a radio frequency signal of the fourthregion are simultaneously transferred, the third switch is configured toconnect the second path, the inductor, the capacitor, and the ground.12. The radio frequency module according to claim 1, wherein the firstband-elimination filter circuit includes: an acoustic wave resonatorconnected in series to a ground path that connects the second path and aground; and a fourth switch disposed on the ground path.
 13. The radiofrequency module according to claim 12, wherein the third frequency bandincludes a third region and a fourth region, the fourth region having ahigher frequency range than the third region, and under a condition thata radio frequency signal of the second frequency band and a radiofrequency signal of the third region are simultaneously transferred, thefourth switch is configured to connect the second path, the acousticwave resonator, and the ground.
 14. The radio frequency module accordingto claim 1, wherein at least one of the passband of the first filtercircuit or the passband of the second filter circuit is variable. 15.The radio frequency module according to claim 1, wherein the secondfilter circuit includes a capacitive series-arm circuit disposed on thesecond path, the first band-elimination filter circuit includes acapacitive series-arm circuit and one or more parallel-arm circuits, thecapacitive series-arm circuit being disposed on the second path, and thecapacitive series-arm circuit of the second filter circuit and thecapacitive series-arm circuit of the first band-elimination filtercircuit are directly connected.
 16. A radio frequency module,comprising: an antenna terminal; a second input/output terminal; asecond filter circuit disposed on a second path, having a passband thatis a second frequency band, and configured to attenuate a signal of afirst frequency band, the second path connecting the antenna terminaland the second input/output terminal, the first frequency band beinglower than the second frequency band; and a first band-eliminationfilter circuit disposed on the second path and having an attenuationband that is a partial band of a third frequency band, the thirdfrequency band being higher than the second frequency band, wherein thefirst band-elimination filter circuit is configured to change at leastone of a frequency range of the attenuation band or an amount ofattenuation of the attenuation band.
 17. The radio frequency moduleaccording to claim 16, further comprising: a third filter circuitdisposed on a third path and having a passband that is the thirdfrequency band; and a second band-elimination filter circuit disposed onthe third path and having an attenuation band that is a partial band ofthe second frequency band.
 18. A radio frequency module, comprising: anantenna terminal; a second input/output terminal; a second filtercircuit disposed on a second path, having a passband that is a secondfrequency band, and configured to attenuate a signal of a firstfrequency band, the second path connecting the antenna terminal and thesecond input/output terminal, the first frequency band being higher thanthe second frequency band; and a first band-elimination filter circuitdisposed on the second path and having an attenuation band that is apartial band of a third frequency band, the third frequency band beinglower than the second frequency band, wherein the first band-eliminationfilter circuit is configured to change at least one of a frequency rangeof the attenuation band or an amount of attenuation of the attenuationband.
 19. The radio frequency module according to claim 18, furthercomprising: a third filter circuit disposed on a third path and having apassband that is the third frequency band; and a second band-eliminationfilter circuit disposed on the third path and having an attenuation bandthat is a partial band of the second frequency band.
 20. A communicationdevice, comprising: an antenna; a radio frequency (RF) signal processingcircuit configured to process a radio frequency signal to be transmittedby the antenna and a radio frequency signal received by the antenna; andthe radio frequency module according to claim 1 configured to transferthe radio frequency signals between the antenna and the RF signalprocessing circuit.